The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Deposition of conformal films at lower temperatures is currently performed using plasma-enhanced chemical vapor deposition (PECVD) using costly, non-generic chemistry that is not widely used in the semiconductor industry. Some deposition techniques used to form conformal films, such as atomic layer deposition (ALD), have complicated sequencing with critical timing steps. As a result of these requirements, yields tend to be lower and cost tends to be higher.
Typical silane (SiH4) based CVD starts to occur in a reactor at ˜650° C. pedestal temperature, however the deposited film is typically non-uniform. Decomposition of the SiH4 alone by pyroltic reaction forms amorphous silicon. Adding hydrogen to the reaction results in hydrogenated amorphous silicon, however the pedestal operating temperature still needs to be above ˜650° C. for deposition to occur.